On one of my Ducatis the clutch is giving me grief. I had a bad wrist injury many years ago and get significant pain with a heavy clutch. It seems a shame to sell a bike just because of this one thing but at mo I can only ride about 40-50 miles before I’m in agony. Soooooo…… I have a possible idea but cannot find anyone who has done it (suggests it might not be a good idea perhaps?) which is to change the ratio by sleeving the master cylinder. My plan is to buy a generic master cylinder and then turning up a sleeve to insert into the bore and a new plunger. I have a lathe/ milling machine and decent range of tools so not worried about making it - though thin walls can be a challenge on a small lathe but I have a plan for that. Just wondering if anyone might have come across this idea before? If so did it produce a significant change in clutch feel? I appreciate it will reduce travel and I may get some drag and I would add that I would never advocate this for brakes, but for a clutch the worse case scenario is a ride on the RAC wagon.
You don't mention which Ducati or whether the current slave cylinder is original. On many Ducatis, swapping for an Oberon (possibly other aftermarket makes) makes the clutch pull lighter. I think this is due to the cylinder being a different size. They are a direct replacement so unbolt the original and bolt on the new one. Much easier than modifying a master cylinder, that would require precise machining and good surface finish.
Used on cars, have a look at inline electric brake/clutch boosters. If small enough, you may be able to incorporate one into the clutch hydraulic system.
I don't know if you've seen this chart, but with with a bit of juggling you may not have to resort to any specialist machining yet. There are many threads on here from memory, and some users with problems due to injury found that the inevitable further throw at the handlebar lever was something they couldn't tolerate despite there being less effort required.
If your not too concerned about a bit of slipping, many years ago there were threads on making the clutch lighter, they did it by removing a couple of springs
As suggested above, surely the best/simplest thing to do is fit an Oberon slave cylinder? Significantly lightens the pull action. Then go from there. If that isn’t enough I’d talk to them and see if they can modify one of theirs to make it even lighter. They’ll probably know the answer.
Smaller master, larger slave, both does what you want. Taking out a couple of springs or finding lighter springs is a good idea. Keeps the lever throw the same and reduces force. Considering the clutch has 2mm tolerance on the plate/disc stack and the springs are still able to prevent slip at the lower stack height some lighter springs, perhaps 20%, are more than likely going to be fine and help with force at the lever.
Indeed, I ran my 916 with just 4 springs for a good few years and never had any slippage. That, combined with a larger slave cylinder meant the clutch was really light. I first did it when I swapped the springs for stainless replacements which were stronger than the originals so can't say whether 4 OEM springs would be the same. You could even try with just 3 springs...
Spring removal is best place to start, zero cost and very quick/easy to do. Can also be reversed back just as easily if it ends up not working. No brainer!
I purposely didn’t mention the model as previous experience on here is that a mod goes ‘ooo, put that in the model specific page’ which is sadly tumbleweed territory and the basic principles apply to any hydraulic system so I wanted the best chance of getting peoples experiences.
I hadn’t and that is incredibly helpful. Thanks! I think I will try the springs first and then have a nose to see if anything on there might work.
I don't blame you, spring mods are far easier, and there are other tricks other than removing two spring posts completely. A lot of the aftermarket stainless steel springs are far stiffer than the original spec springs, which doesn't help.
You can put plain washers between the top hat washer and the clutch pressure plate to reduce the spring tension, but bear in mind that it will reduce the clearance between the top of the allen head and the inside of the clutch case, I did this on my S4rt and made a spacer for the clutch case to account for it, I think Dukedesmo still has it?
‘Integral slave’ ??? Are you saying the slave cylinder, the one by the front sprocket, cannot be removed from the bike?
